Question about 1998 GMC Sierra

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My code reader says PO308. Put on new spark plug, wire, cap, coil, coil module. code still come up. Truck has 175000 miles on it

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It is most likely the fuel injector,replace it and you will be on your way.

Posted on May 12, 2010


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2 Answers

I got no spark won't start. 93 1500 Chevy truck 4.3 motor

How long since a tune-up?
Check for applicable trouble codes, if there are any? Your obd 1, you should be able to check for some codes, if the mil still works.
Check primary voltage at the coil, pink wire, key on. Use a test light to check for voltage.
The spark plugs--plug wires--dist cap and rotor all good? Does the rotor turn when you crank it? If you take coil wire loose from distributor cap and hold close to engine ground, have helper crank it, do you see a spark jump? I don't know what testing you have done?
With bypass ignition it's the ignition module that controls spark during cranking. With the coil itself, key on, should be voltage on both sides, if only one side, the coil is faulty. The ground for the coil should pulse, with engine cranking. I'm sure I've left something out? You need to do some testing.

Apr 17, 2016 | Cars & Trucks

1 Answer

No Spark At the Coil
He might help you as he is an expert in cars ;)

Mar 11, 2013 | Cars & Trucks

1 Answer

Engine on my 2000 dodge durango is reving up and down showing codes po305 , po300, po308

for these codes
If there are symptoms such as the engine is stumbling or hesitating, check all wiring and connectors that lead to the cylinders (i.e. spark plugs). Depending on how long the ignition components have been in the car, it may be a good idea to replace them as part of your regular maintenance schedule. I would suggest spark plugs, spark plug wires, distributor cap, and rotor (if applicable). Otherwise, check the coils (a.k.a. coil packs). In some cases, the catalytic converter has gone bad. If you smell rotten eggs in the exhaust, your cat converter needs to be replaced. I've also heard in other cases the problems were faulty fuel injectors.

Aug 31, 2011 | Chrysler Town and Country Cars & Trucks

4 Answers

I want to replace spark plugs (8) and wires on my '84 GMC pickup

get a 20 dollar haynes or chiltons manuel and find the module and coil. always change the ignition module and coil every 4 no more than -5 years to be safe.

Feb 10, 2010 | GMC Sierra 2500 Cars & Trucks

1 Answer

Po308 code misfire #8 cylinder. How to fix? replace ignition module first? spark plugs were just done and seem fine.

Seems you may have answered your own question.

P0308 will normally be a coil failure but can also be a compression fault caused by a sticky lifter etc or a faulty, incorrectly gapped spark plug

It most likely be the coil but check the spark plug and run a compression test if you have the equipment, all bores should have equal PSi readings.

Or you could try moving the coil in cyl. 8 to see if the code moves to a different P030* code

Dec 06, 2009 | Dodge Durango Cars & Trucks

5 Answers

1988 chevy 350 problem

The crank angle sensor maybe bad. It sends a signal to the computer so the spark plugs fire up.

Sep 09, 2009 | Cars & Trucks

3 Answers

97 gmc sierra shut off well driving and wont start anymore but it turns over?

I really dont think its the ignition module.Those are a little expensive so i wouldnt buy one until you sure thats the problem.I would turn the key to the on position and listen for the fuel pump.The pump only runs for about 3-5 secs when you first do it.If you dont hear anything thats the ploblem.If you can hear the pump come on try to use starting fluid to get it started.If it starts and runs fine then the fuel pump doesnt put out enough pressure to start the truck and need to be replaced.If that doesn t work take a spark plug out of the motor and plug it back into the wire.When you try to start the truck it should make a bright blue spark.If the spark is not bright and fast it could be many things like that plug or that wire all the plugs and wires or the distibutor cap or the rotor.It could also be the coil.If you have the money you should replace all of that stuff.If your on a budget like me I would change the distibutor cap and rotor and see if that help.If the plugs and wires are fairly new change the coil.You should do your plugs and wires after so many mile or time period.Im sure its not the Ignition control module.The guy at the part store always says that might be the problem and ive never bought one yet.My truck has 250,000 miles on it and still going.

Sep 06, 2009 | 1997 GMC Sierra

2 Answers

No spark, just put in a new coil, distrbutor isnt dirty or wet, sombody told to check out the littl box's on the fender well, what are these to box's and what is there purpose? Mike 77 cj-5 304 3spd I...

I had the same problem with my 85 cj7 this week, I relpaced the ignition control module, plugs, wires, cap, rotor and the the coil; still had no fire to plugs. the problem turned out to be my distributor, replaced it today and she fired right up. Most likely it was the pick up module in the distributor that went bad.

Nov 30, 2008 | 1983 Jeep CJ7

1 Answer

1990 dodge b350 no spark

Yes you most likely have a ign module problem, the pickup hardly ever fails. If the truck is really hi miles repace the plug wires as well.

Oct 03, 2008 | 1988 Dodge B350

2 Answers

2000 GMC Sierra 4.3L no spark at the plugs...HELP!

no codes. most direct components changed.
computer. take it out or have the truck towed to the shop/dealer to test the computer.

Sep 25, 2008 | 2000 GMC Sierra

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